View Full Version : HF Milling machines....
09-10-2004, 10:43 AM
I've been thinking about getting a HF milling machine, but I wanted to hear from people that own one first.. I've found several large price gaps between them too which I don't understand. What's the difference between the $400, $700, and $2000 versions? I've never used a milling machine before so I want to get one to both learn, and fabricate misc parts (No plans yet for an specific parts -- I guess that will depend on what I can/can't do with a milling machine).
Any advise for HF milling machines?
Yeah- dont buy one. Harbor Freight is generally the runt of the litter- and they have no conception of what customer service is, much less stocking parts or warranty repairs. This is fine when you are buying something for 10 bucks with no moving parts. But for a precision tool like a milling machine, it is a recipe for disaster. Plus all they care about is low price- so even if you see 3 milling machines from 3 different companies that look the same, the HF one is pretty much sure to have lower quality fasteners and electrics, lower tolerances, and worse assembly.
Instead, in the price range you are looking at, Go either Grizzly or Jet. Both specialize in machine tools, not general merchandise, and when you call them up, they have parts in stock and will stand behind their products. Both are a little more expensive than harbor freight, but believe me, this is a case of getting what you pay for. Personally, I think Jet is higher quality than Grizz, but Grizz has a better selection of low end machines, and their service and parts are very good.
If you know nothing about milling machines, you might want to consider a class at you local community college- often night classes are available. I would also buy a book like "Machine Tool Practices" or "Milling Machine Operations" both by Richard Kibbe and published by John Wiley. You should be able to pick them up reasonably cheap used on ABEbooks.com,
A decent starter machine would be something like this:
The table is big enough to do some decent size work, it has a pretty big motor- and if you outgrow it, you can always sell it to another newbie on his way up. I wouldnt go any smaller than this size- they get pretty toylike.
Next step up is a bridgeport clone like this:
A lot more money, but a real tool that will do all kinds of stuff.
Now a lot of people will tell you not to mess with the chinese imports at all, and just get a used bridgeport- and since you are in Ma, this should be pretty easy- there are tons of them there. The advantages to a used american machine are- bigger, heavier, better built, lots of accesories and repair parts available. But it takes more experience to tell if they are worn out or not, and they are bigger and heavier, thus harder to move around, usually 3 phase, and there are some orphans out there that are hard to find tooling for. Chinese machines, on the other hand, usually just plug in and run, and you get to wear em out yourself.
Really a matter of personal preference, and patriotism. Some people really love old classic american iron, others want the convenience of a toyota- your choice.
09-14-2004, 12:37 PM
I keep thinking about buying a used milling machine to play with. To me the tilting (both front to back and sideways) would be an essential feature of the machine. The one at the first link seems to have no tilting capability while the one at the second link seems to have that capability.
I keep hopeing to stumble across an old bridgeport someday for $1000-1500. I keep looking at Ebay but most of them seem to be in California, Michigan or NY. Just a little too expensive to ship that far and I'd probably want to see it first hand before paying anyway.
03-15-2005, 01:15 PM
The first link is a mill-drill.
I've lived with one similar (Jet) for 10 years or so. It is an AWSOME drill press. It is a barely adequate mill.
The head can only be trammed by shimming the base to column mounting. Because there is a slight flexing of the base and/or column, the load changes with the elevation of the head, so tramming is only good at one head height. It may only be half a thou off over 4" but that is enough to put a visable step when you are trying to fly-cut a large surface.
Lack of rigidity: The column is a torsion spring. A stiff one, but compare that to the column on a bridgeport. This seriosly limits how heavy a cut and/or feed rate you can take. If you put a "real" 6" milling vice with angle base on the table, you have to run the head up about 4-5" higher, so you get more of the spring effect. On a milling machine, rigidy is Extreamly important. The more rigid the machine, the more effieciently you can work (heavier cuts) and the better surface finish, and fewer broken tools, ruined parts, etc.
Y axis travel: Is like 5" . This is frequently a limitation, most noticeable when trying to drill, say a 4" bolt circle. If the pattern isn't centered in the travel range, you get to the last hole, and find out you can't reach it. So you have to do more layouts so you can check the travel before you start.
Z axis travel: Is even less....around 4" I think. This really becomes an issue with changing tooling. Screw machine length drill bits help a lot here. Sometimes I end up running an EM in a collet instead of a Weldon holder, just to save the length. Yes you can run the column up and down, but then you lose your X and Y zeros.
Z axis drift: You lock the quill when you take a cut. The vibration of the cut causes the Z-dial to drift due to it's backlash. If you fail to note the previous setting (where you set it, not where you found it) , then you may dial in the wrong depth for the next cut.
Z axis rigidity: The only Z travel is via the quill (there is no knee) This means that the rigidity of the Z axis changes as you extend the quill. So when you use a boring head, it cuts a slightly tapered hole. Because of the column, the rigidy is different in Y direction than X direction, so the hole will also be slightly eliptical. You can minimize both problems by taking lighter cuts, but that takes time.
Belt/speed changing: First thing you will do is remove the belt guard and throw it in the attic. It is just in the way, and you can't open it without running the head all the way up anyway. Keep your hair short, and the belts are up where they will never be a safety issue anyway. Even with the gaurd off, it is enough hassle to change speeds that you will often run things too fast or too slow just to save the hassle.
These problems aside, it is MUCH better than having no mill at all, and I'd only give it up for something better. I have access to a "real" mill at work, so have a workaround for things that the M-D just won't do.
Also, as I said, the machine is head and shoulders above any drill-press, and that is the reason you seldom see them for sale. Even when a M-D owner upgrades to a better mill, the M-D is kept around as a super drill press, or for small jobs that come up to avoid tearing down a setup on the "real" mill. The resale value isn't enough to be worth the hassle of trading down to a drill press.
03-18-2005, 08:26 PM
I bought my first mill about six years ago, an old Index- now Wells-Index. It was made in 1928, and uses Brown and Sharp #9 tooling. Beware old machines, unless you are familiar with the enormous multitude of things that can go wrong with them. I got my money's worth from that machine, after replacing the X and Y acme nuts, specially machined to the odd screw size/pitch, scraping the ways, and rebuilding all the gibs, including the knee. I still don't have regular downfeed, haven't been able to figure out how to get the acme out of that one, and the machine has consumed more than its share of $100 cutters. Now it looks like the quill splines are on their way out. Time for a new machine...
03-21-2005, 08:34 PM
got my mill from wttool.com .must have a dovetail colum so you can up and down without lossing center . the round colum you will lose center drive you nuts!!!! my .02 cents
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